New Powerful Machines

    entity-wharf

    0.1.1 • Public • Published

    What it does

    Stores your data in an elegant way that will give you great flexibility and leverage. This library is designed to be used as a state management solution for applications that need to be performant for quickly mutating state over many different types of entities with similar characteristics. Applications such as games and simulations. If performance isn't this crucial then check out DataScript which provides immutability, versioning, undo/redo, and a powerful datalog query engine.

    All data stored in Wharf is organized uniformly as

    • Entity - just an id (i.e. 1)
    • Attribute - an attribute of the entity (i.e. name or age)
    • Value - the value of the attribute (i.e. "bob" or 50)

    For example let's describe some shapes.

    • entity 1 is a blue square
    • entity 2 is a red triangle
    • entity 3 is a red circle
    Entity Attribute Value
    1 color blue
    1 width 20
    1 height 20
    1 n_edges 4
    2 color red
    2 base 10
    2 height 40
    2 n_edges 3
    3 color red
    3 radius 20
    3 n_edges 0

    Although there are 3 distinct types we can perform generic queries that cross types.

    All entities that have a height attribute returns [ 1, 2 ]

    Entity Attribute Value
    1 height 20
    2 height 40

    All entities that have a height and a width attribute returns [ 1 ]

    Entity Attribute Value
    1 width 20
    1 height 20

    All entities with a value 20 returns [ 1, 3 ]

    Entity Attribute Value
    1 width 20
    1 height 20
    3 radius 20

    All entities where color == red returns [ 2, 3 ]

    Entity Attribute Value
    2 color red
    3 color red

    How to use it

    var db = Wharf();//make a new "db" to work with
     
    //create some entities
    var square_id   = db.add({color: "blue", width: 20, height: 20, n_edges: 4});// (returns false on failure)
    var triangle_id = db.add({color: "red", base: 10, height: 40, n_edges: 3});
    var circle_id   = db.add({color: "blue", radius: 20});
     
    //db.set will add/overwrite attributes and values on an entitiy
    db.set(circle_id, {color: "red", n_edges: 0});// -> true (returns false on failure)
     
    //db.get returns the entities data
    db.get(circle_id);// -> {color: "red", radius: 20, n_edges: 0} (returns null if it's not found)
     
    //At this point the db has 3 entities the same as in the example
     
    //All entities that have a `height` attribute
    db.q({a: ["height"]});// -> [ square_id, triangle_id ]
     
    //All entities that have a `height` and a `width` attribute
    db.q({a: ["height", "width"]});// -> [ square_id ]
     
    //All entities with a value `20`
    db.q({v: [20]});// -> [ square_id, circle_id ]
     
    //All entities where `color == red`
    db.q({av: [["color", "red"]]});// -> [ triangle_id, circle_id ]
     
    //entities are easy to remove
    db.remove(square_id);// -> true
     
    //if an ID doesn't exist it returns false
    db.remove(square_id);// -> false

    Installing

    There are 3 ways to include this library

    With browserify

    $ npm install --save entity-wharf

    Then use it

    var Wharf = require('entity-wharf');
    ...

    With a script tag

    Download this script then include it in your html

    <script src="entity-wharf.min.js"></script>

    Then use it

    var Wharf = ENTITY_WHARF;
    ...

    With RequireJS

    Download and use this minified script then require it

    require(['entity-wharf'], function(Wharf) {
        ...
    });

    License

    The MIT License (MIT)

    Copyright (c) 2014 Small Helm LLC

    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Install

    npm i entity-wharf

    DownloadsWeekly Downloads

    4

    Version

    0.1.1

    License

    MIT

    Last publish

    Collaborators

    • farskipper